Banjul, Gambia (PANA) - Ghana's outgoing president John Dramani Mahama has arrived in the Gambian capital, Banjul, where he will join leaders of the Economic Community of West African States (ECOWAS) to mediate in the looming political crisis in Gambia.

"In Banjul, with other colleague Heads of State from the subregion, to help mediate post election issues in The Gambia," he tweeted.

Gambia is facing a political crisis after President Yahaya Jammeh rejected the results of the country's 1 December election and called for a fresh vote.

Mahama himself only last week lost an election and conceded defeat. He has put into motion transitional measures towards the inauguration of president-elect Nana Akufo-Addo on 20 January 2017.

State-owned Gambia Radio and Television on Monday night announced that leaders of the Economic Community of West African States (ECOWAS) were due in Banjul, Gambia, on Tuesday for talks to persuade incumbent president Jammeh to agree to leave office after his defeat in the election.

It said the delegation headed by Liberian president Ellen Johnson Sirleaf, current chairperson of ECOWAS, would include Nigerian President Muhammadu Buhari and Sierra Leone President Ernest Bai Koroma.

President Jammeh initially conceded defeat to opposition leader Adama Barrow but later rejected the result saying there were "unacceptable abnormalities" which transpired during the electoral process.